1. Field of the Invention
This invention relates to an improvement in a die structure for use in forming seals about the junctions between electrical wires, and in one aspect to an improved elastomeric generally cylindrical die plate which will afford improvement in placing a sealant around the junction and around each of the wires leading to the junction to make a good moisture seal.
2. Description of the Prior Art
It is known to place a sealant pad about the junction between several wires and then to place the pad and wire junction between metal dies in a press and allow the press to close to force the sealant on the sealant pad into contact and seal water or contaminants from the junction. In known instances however, where there is a plurality of wires, or bundle of wires, coming into one side of the pad the sealant on the sealant pad did not flow firmly about each of the wires and into intimate contact with each of the wires. This allows moisture to migrate along the wire to the junction and cause contamination. The prior die plates comprised identical metal plates mounted as mirror images and the plates included a recess having opposite side walls or ridges. The recess was a generally concave depression having a radius sufficient to receive a particular wire size. The recess and end surfaces generally define flow directing means which directed the sealant flow in a preferred manner. The radiused recess area of the die plates is formed about an axis transverse to the direction the wires were to extend from the die plates and, with flat areas opposite each other at the sides of the sealant pads, the sealant in the pads did not suitably surround and seal the wires in the wire harness or cable. This prior art structure is disclosed in U.S. Pat. No. 4,863,535, issued on application Ser. No. 07/130,541 filed Dec. 9, 1987.
In electrical harness applications, such as for automobiles, there is a need to environmentally seal splices comprised of several wires. This is accomplished by wrapping a sealant about the wires and their junction. Forcing a sealant between the wires to afford a moisture tight seal can be very difficult, particularly if some stacking of the wires exists in the wire bundle. The present invention affords a method by which the wires are spread during the application of the sealant pad.
The present invention will provide the seal in substantially the same manner as the seal of the prior die plates but there is substantial improvement in the separation of the wires, the distribution of the sealant about the wires and any air in the pad, trapped when the pad is initially folded about the wire junction, is forced from the junction as the die plates are forced against the opposite sides of the sealant pad.
The present invention provides a pair of die plates for use in forming a water impermeable seal about a wire junction formed between two or more wires by engaging the pad on opposite sides along the middle portions of the pad to apply a squeezing force in the middle of the pad which force progresses toward the edges as the face of the die plates is deformed to tightly compress the entire pad between the plates.
The product of this invention provides a die plate which conforms to a wider range of wire diameters, it serves to spread the wires and force the sealant between wires in a bundle of wires of a wide range of wire sizes, whether they are the same or different diameters, entering or exiting the junction, and it reduces the possibility of wire insulation damage during pressing of the sealant. The present invention also restricts damage to the junction.